[ dì sān jì ]

新生代的一个纪。约开始于6 500万年前，结束于160万年前。现已进一步分为古近纪和新近纪。参见〔古近纪〕、〔新近纪〕

tertiary (geological era since the extinction of the dinosaurs at the Cretaceous-Tertiary boundary 65 million years ago); third period